A constitutive model is developed to capture the rate-dependent stressstrain behavior of an amor... more A constitutive model is developed to capture the rate-dependent stressstrain behavior of an amorphous polymer (poly(ethylene terephthalate)-glycol (PETG)) at temperatures in and above the glass transition (θ g ). As a polymer goes through its glass transition, it exhibits a ...
This paper investigates the mechanical behavior of electrospun polycaprolactone (PCL) under tensi... more This paper investigates the mechanical behavior of electrospun polycaprolactone (PCL) under tensile loading. PCL in bulk form degrades slowly and is biocompatible, two properties that make it a viable option for tissue engineering applications in biomedicine. Of particular interest is the use of electrospun PCL tubes as scaffolds for tissue engineered blood vessel implants. Stress relaxation and tensile tests have been conducted with specimens at room temperature (21 degrees C) and 37 degrees C. Additionally, to probe the effects of moisture on mechanical behavior, specimens were tested either dry (in air) or submerged in water. In general, the electrospun PCL was found to exhibit rate dependence, as well as some dependence on the test temperature and on whether the sample was wet or dry. Two different models were investigated to describe the experimentally observed material behavior. The models used were Fung's theory of quasilinear viscoelasticity (QLV) and the eight-chain model developed for rubber elastomers by Arruda and Boyce (1993, "A Three-Dimensional Constitutive Model for the Large Stretch Behavior of Rubber Elastic Materials," J. Mech. Phys. Solids, 41(2), pp. 389-412). The implementation and fitting results, as well as the advantages and disadvantages of each model, are presented. In general, it was found that the QLV theory provided a better fit.
Poly(ethylene terephthalate) is widely used for consumer products such as drawn fibers, stretched... more Poly(ethylene terephthalate) is widely used for consumer products such as drawn fibers, stretched films, and soda bottles. Much of its commercial success lies in the fact that it crystallizes at large strains during warm deformation processing. The imparted crystallinity increases its ...
Finite Element Modeling of Reheat Stretch Blow Molding of PET. [AIP Conference Proceedings 712, 2... more Finite Element Modeling of Reheat Stretch Blow Molding of PET. [AIP Conference Proceedings 712, 228 (2004)]. Dwarak Krishnan, Rebecca B. Dupaix. Abstract. Poly (ethylene terephthalate) or PET is a polymer used as a packaging ...
Journal of engineering materials and …, Jan 1, 2006
Recently, a hyperelastic-viscoplastic constitutive model was developed for PET and the noncrystal... more Recently, a hyperelastic-viscoplastic constitutive model was developed for PET and the noncrystallizing copolymer PETG (RB Dupaix, Ph.D. thesis, MIT, 2003). The materials were found to behave very similarly under monotonic loading conditions and the single constitutive model was able ...
An understanding of the mechanical deformation behavior of the liver under high strain rate loadi... more An understanding of the mechanical deformation behavior of the liver under high strain rate loading conditions could aid in the development of vehicle safety measures to reduce the occurrence of blunt liver injury. The purpose of this study was to develop a constitutive model of the stress-strain behavior of the human liver in blunt impact loading. Experimental stress and strain data was obtained from impact tests of 12 unembalmed human livers using a drop tower technique. A constitutive model previously developed for finite strain behavior of amorphous polymers was adapted to model the observed liver behavior. The elements of the model include a nonlinear spring in parallel with a linear spring and nonlinear dashpot. The model captures three features of liver stress-strain behavior in impact loading: (1) relatively stiff initial modulus, (2) rate-dependent yield or rollover to viscous "flow" behavior, and (3) strain hardening at large strains. Six material properties were used to define the constitutive model. This study represents a novel application of polymer mechanics concepts to understand the rate-dependent large strain behavior of human liver tissue under high strain rate loading. Applications of this research include finite element simulations of injury-producing liver or abdominal impact events.
The 41st Annual SES Technical Meeting, Jan 1, 2004
To better understand the role of strain-induced crystallization in PET, its behavior is compared ... more To better understand the role of strain-induced crystallization in PET, its behavior is compared to a non-crystallizing copolymer, PETG. A constitutive model of the rate and temperature dependent stress-strain behavior is developed based on experimental data for PETG and is then ...
A constitutive model is developed to capture the rate-dependent stressstrain behavior of an amor... more A constitutive model is developed to capture the rate-dependent stressstrain behavior of an amorphous polymer (poly(ethylene terephthalate)-glycol (PETG)) at temperatures in and above the glass transition (θ g ). As a polymer goes through its glass transition, it exhibits a ...
This paper investigates the mechanical behavior of electrospun polycaprolactone (PCL) under tensi... more This paper investigates the mechanical behavior of electrospun polycaprolactone (PCL) under tensile loading. PCL in bulk form degrades slowly and is biocompatible, two properties that make it a viable option for tissue engineering applications in biomedicine. Of particular interest is the use of electrospun PCL tubes as scaffolds for tissue engineered blood vessel implants. Stress relaxation and tensile tests have been conducted with specimens at room temperature (21 degrees C) and 37 degrees C. Additionally, to probe the effects of moisture on mechanical behavior, specimens were tested either dry (in air) or submerged in water. In general, the electrospun PCL was found to exhibit rate dependence, as well as some dependence on the test temperature and on whether the sample was wet or dry. Two different models were investigated to describe the experimentally observed material behavior. The models used were Fung's theory of quasilinear viscoelasticity (QLV) and the eight-chain model developed for rubber elastomers by Arruda and Boyce (1993, "A Three-Dimensional Constitutive Model for the Large Stretch Behavior of Rubber Elastic Materials," J. Mech. Phys. Solids, 41(2), pp. 389-412). The implementation and fitting results, as well as the advantages and disadvantages of each model, are presented. In general, it was found that the QLV theory provided a better fit.
Poly(ethylene terephthalate) is widely used for consumer products such as drawn fibers, stretched... more Poly(ethylene terephthalate) is widely used for consumer products such as drawn fibers, stretched films, and soda bottles. Much of its commercial success lies in the fact that it crystallizes at large strains during warm deformation processing. The imparted crystallinity increases its ...
Finite Element Modeling of Reheat Stretch Blow Molding of PET. [AIP Conference Proceedings 712, 2... more Finite Element Modeling of Reheat Stretch Blow Molding of PET. [AIP Conference Proceedings 712, 228 (2004)]. Dwarak Krishnan, Rebecca B. Dupaix. Abstract. Poly (ethylene terephthalate) or PET is a polymer used as a packaging ...
Journal of engineering materials and …, Jan 1, 2006
Recently, a hyperelastic-viscoplastic constitutive model was developed for PET and the noncrystal... more Recently, a hyperelastic-viscoplastic constitutive model was developed for PET and the noncrystallizing copolymer PETG (RB Dupaix, Ph.D. thesis, MIT, 2003). The materials were found to behave very similarly under monotonic loading conditions and the single constitutive model was able ...
An understanding of the mechanical deformation behavior of the liver under high strain rate loadi... more An understanding of the mechanical deformation behavior of the liver under high strain rate loading conditions could aid in the development of vehicle safety measures to reduce the occurrence of blunt liver injury. The purpose of this study was to develop a constitutive model of the stress-strain behavior of the human liver in blunt impact loading. Experimental stress and strain data was obtained from impact tests of 12 unembalmed human livers using a drop tower technique. A constitutive model previously developed for finite strain behavior of amorphous polymers was adapted to model the observed liver behavior. The elements of the model include a nonlinear spring in parallel with a linear spring and nonlinear dashpot. The model captures three features of liver stress-strain behavior in impact loading: (1) relatively stiff initial modulus, (2) rate-dependent yield or rollover to viscous "flow" behavior, and (3) strain hardening at large strains. Six material properties were used to define the constitutive model. This study represents a novel application of polymer mechanics concepts to understand the rate-dependent large strain behavior of human liver tissue under high strain rate loading. Applications of this research include finite element simulations of injury-producing liver or abdominal impact events.
The 41st Annual SES Technical Meeting, Jan 1, 2004
To better understand the role of strain-induced crystallization in PET, its behavior is compared ... more To better understand the role of strain-induced crystallization in PET, its behavior is compared to a non-crystallizing copolymer, PETG. A constitutive model of the rate and temperature dependent stress-strain behavior is developed based on experimental data for PETG and is then ...
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Papers by Rebecca B. Dupaix